Regulation of plasma glucose and sulfate excretion in Pacific hagfish, Eptatretus stoutii is not mediated by 11-deoxycortisol.

Abstract The goal of this study was to identify whether Pacific hagfish ( Eptatretus stoutii ) possess glucocorticoid and mineralocorticoid responses and to examine the potential role(s) of four key steroids in these responses. Pacific hagfish were injected with varying amounts of cortisol, corticosterone or 11-deoxycorticosterone (DOC) using coconut oil implants and plasma glucose and gill total-ATPase activity were monitored as indices of glucocorticoid and mineralocorticoid responses. Furthermore, we also monitored plasma glucose and 11-deoxycortisol (11-DOC) levels following exhaustive stress (30 min of agitation) or following repeated infusion with SO 4 2− . There were no changes in gill total-ATPase following implantation with any steroid, with only very small statistical increases in plasma glucose noted in hagfish implanted with either DOC (at 20 and 200 mg kg −1 at 7 and 4 days post-injection, respectively) or corticosterone (at 100 mg kg −1 at 7 days post-injection). Following exhaustive stress, hagfish displayed a large and sustained increase in plasma glucose. Repeated infusion of SO 4 2− into hagfish caused increases in both plasma glucose levels and SO 4 2− excretion rate suggesting a regulated glucocorticoid and mineralocorticoid response. However, animals under either condition did not show any significant increases in plasma 11-DOC concentrations. Our results suggest that while there are active glucocorticoid and mineralocorticoid responses in hagfish, 11-DOC does not appear to be involved and the identity and primary function of the steroid in hagfish remains to be elucidated.